1. Field of the Invention
The invention relates to a grinding machine, more particularly to a grinding machine with a fireproof dust-collecting system.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional grinding machine 10 includes a casing 12 with a top plate unit 12A disposed at a top end portion of the casing 12, two grinding units or grinding wheels 11 installed on two side portions of the top plate unit 12A, a driving unit 12B for activating the grinding units 11, a dust-collecting chamber 15 disposed in a lower end portion of the casing 12, and a filtering unit 16 installed in the casing 12 under the top plate unit 12A. As illustrated, each of the side portions of the top plate unit 12A has a dust inlet slot 111 formed therethrough so as to permit dropping of dust from a corresponding one of the grinding units 11 into the dust inlet slot 111. Each of the grinding units 11 is further provided with two shielding sheets 13, 14 which facilitate dropping of dust into the dust inlet slot 111 of the casing 12. A plurality of air discharge outlets 122 are located below the top plate unit 12A.
Some of the drawbacks resulting from the use of the conventional grinding machine 10 are as follows:
(I) During the grinding operation, sparks of fire are generated. Since the filtering sheets used in the filtering unit 16 are generally made from flammable material, such as non-woven fabrics, the fire sparks may accidentally ignite the filtering sheets. PA1 (II) Only a particular size of grinding wheel can be employed with the grinding units 11, thereby limiting undesirably the range of use of the grinding machine 10.